The present invention relates to semiconductor devices and more particularly to power semiconductor switches that include a superjunction arrangement.
Superjunction MOSgated devices commonly comprise a plurality of spaced pillars or stripes of one of the conductivity types which extend perpendicularly into a silicon body of the other of the conductivity types that serves as the drift region. A MOSgate structure enables the connection of a source voltage to the pillars or stripes relative to the body, which is connected to a drain voltage. In a superjunction arrangement, the total charge in the pillars or stripes is at least approximately balanced by the charge in the surrounding silicon body. Thus, the body region and pillars or stripes are fully depleted in reverse bias to block reverse voltage. The concentration of dopants in the body may then be increased (decreasing its resistivity), as compared to that of the conventional MOSFET, so that during forward bias, the on resistance is reduced.